1. Field of the Invention
The present invention relates to an air conditioning system and an apparatus for protecting the same, and more particularly, to an air conditioning system capable of preventing a liquid refrigerant of a high pressure and a high temperature from being introduced into an outdoor unit under a state an expansion valve of an indoor unit is opened when power supply to the indoor unit is cut off due to a static electricity or a short circuit, etc., and an apparatus for protecting the same.
2. Description of the Background Art
Generally, an air conditioning system serves to control a temperature, a humidity, a stream, and a cleanliness degree of air for a comfortable indoor environment. The air conditioning system is classified into an integral type constructed as an indoor unit and an outdoor unit are installed in a single case, and a separated type constructed as a compressor and a condenser are installed at an outdoor unit and an evaporator is installed in an indoor unit.
Recently, a multi-type air conditioning system having a plurality of indoor units for cooling or heating each space of an indoor room is increasing.
FIG. 1 is a construction view showing a multi-type air conditioning system in accordance with the conventional art.
As shown, the conventional multi-type air conditioning system 1 comprises a plurality of indoor units 10, and an outdoor unit 20 connected to each indoor unit 10 for compressing a refrigerant.
Each of the indoor units 10 is disposed at an indoor room. The indoor unit 10 is composed of an indoor heat exchanger 11 for heat-exchanging a refrigerant, and an indoor expansion valve 13 connected to the indoor heat exchanger 11 for depressurizing and expanding a refrigerant.
The outdoor unit 20 includes a plurality of compressors 23 for compressing a refrigerant, an accumulator 35 connected to an inlet refrigerant line of the compressor 23 for providing a gaseous refrigerant of a low temperature and a low pressure to the compressor 23, and a plurality of outdoor heat exchangers 41 connected to the compressor 23 for heat-exchanging a refrigerant.
An oil balancing pipe 25 is connected between each of the compressors 23, and an oil separator 27 for separating a refrigerant from oil is installed at an is outlet refrigerant line of each compressor 23. An oil returning line 28 for returning oil separated from a refrigerant to the compressor 23 is installed at the oil separator 27, and a check valve 29 is installed at an outlet refrigerant line of the oil separator 27.
A four-way valve 31 for switching a refrigerant flow is installed at an outlet refrigerant line of the check valve 29. Three ports 31a of the four-way valve 31 are respectively connected to an outdoor heat exchanger 41, an accumulator 35, and an indoor unit 10 by each refrigerant line.
A check valve 43 and an outdoor expansion valve 45 are installed at an outlet refrigerant line of each outdoor heat exchanger 41 along a flow direction of a refrigerant at the time of a cooling operation. Also, a service valve 37 is installed at an outlet refrigerant line of the check valve 43 and a refrigerant line of the indoor unit 10.
However, the conventional multi-type air conditioning system has following problems. When power supply to the indoor unit is cut off due to a static electricity or a short circuit, a liquid refrigerant of a high temperature and a high pressure introduced into the indoor unit 10 from the outdoor unit 20 is introduced into the outdoor unit 20 as an abnormal state that the liquid refrigerant is not heat-exchanged by the corresponding heat exchanger 11 under a state that the indoor expansion valve 13 is opened. As the result, not only the compressor 23 but also the entire air conditioning system may be damaged.